Search PubMed⌕ Search

Biomedical subjects

H Klein

Publications and source records attributed to H Klein.

At least 127 records · Page 7Linked to original sources
PubMed1993

[Problems and complications after implantation of automatic defibrillators].

Until now there are only few reports about problems and complications associated with the automatic implantable cardioverter-defibrillator (ICD). Therefore, we studied the follow-up of 295 patients, who underwent ICD therapy. Epicardial ICD implantation was performed in 206 patients (71%) and 89 patients (29%) received transvenous ICD systems. Infections or seroma of the pulse generator and/or lead systems were observed in 18 patients (6%), in nine patients after first ICD implant and in nine patients after generator replacement. General signs of inflammation were present in eleven patients, whereas local signs with seroma of the pocket were observed in seven patients. Explantation of the entire ICD hardware was performed in eleven patients and seven patients underwent partial removal of the ICD system. Lead complications occurred in 15 patients (5%), in eleven patients with epicardial and in four with transvenous ICD systems. All patients had inappropriate ICD shocks and had to undergo lead replacement. Inappropriate ICD shocks due to supraventricular tachyarrhythmias occurred in 24 patients (8%). Other complications (apoplexia, hematoma, pneumothorax) were observed in 15 patients (5%). Our data show that complications associated with the ICD are low. However, these complications can cause big problems and need appropriate diagnosis and treatment.

Adolescent↗
PubMed1993

[The importance of the underlying disease for outcome of patients with implanted automatic defibrillators].

It is unclear whether the outcome of patients with implanted cardioverter defibrillator (ICD) is influenced by the underlying etiology or not. Therefore, we studied the follow-up of 271 patients who underwent ICD implantation for life-threatening ventricular tachyarrhythmias. Coronary artery disease was present in 203 patients (75%) (G1), dilated cardiomyopathy in 36 patients (18%) (G2), while 32 patients (12%) (G3) had an "arrhythmogenic" ventricle (dysplasia, valvular disease, idiopathic arrhythmias). Mean left ventricular ejection fraction was 30 +/- 11% in G1, 33 +/- 13% in G2 and 48 +/- 13% in G3. Perioperatively, 12/271 patients (4%) died. During the mean follow-up of 21 +/- 17 (< 1 to 99) months, 52/259 patients (20%) died: 31% (11/36 patients) in G2, 19% (36/193 patients) in G1 and 17% (5/39 patients) in G3. There was a low incidence of sudden death (SD) (4%, 2% per year) without significant differences between G1 (3%), G2 (8%) and G3 (3%). In addition, no significant differences were observed in cardiac mortality (CD) between G1 (10%), G2 (14%) and G3 (3%) (p = n.s.). ICD discharges occurred in 188 patients (69%); ICD discharges occurred in G1 in 138 patients (68%), in G2 in 27 patients (75%) and in G3 in 23 patients (72%). The mean incidence of ICD discharges per patient was 16 +/- 10 shocks in G1, 24 +/- 8 shocks in G2 and 18 +/- 8 shocks in G3. After ICD implant, complications occurred in 67 patients (23%). Our data show that the ICD is highly effective in preventing sudden death independent on the underlying etiology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The contraction of hepatic stellate (Ito) cells stimulated with vasoactive substances. Possible involvement of endothelin 1 and nitric oxide in the regulation of the sinusoidal tonus.

We have studied the contractility of liver sinusoidal stellate (Ito) cells stimulated with endothelin 1, nitric-oxide donors and eicosanoids. Contraction and relaxation of stellate cells were detected by the use of a silicone-rubber method that revealed the traction forces exerted by these cells. Endothelin 1 was a strong elicitor for stellate-cell contraction. 78, 55, 59 and 56% of stellate cells were contracted 2.5, 5, 10 and 20 min, respectively, after exposure to 10 nM endothelin 1. The effect of endothelin 1 was dose dependent and still detectable at an endothelin 1 concentration of 100 pM. Concomitantly, an endothelin-dependent formation of inositol phosphates was apparent; values of InsP, InsP2, and InsP3 were 881 +/- 99%, 1965 +/- 368%, and 791 +/- 120% of control, respectively, 20 min after addition of 10 nM endothelin 1. In addition, endothelin 1 caused a transient increase of [Ca2+]i in stellate cells from a basal value of 121 +/- 9 nM to maximal 1015 +/- 86 nM. These endothelin-1 effects were much stronger than those of the thromboxane-A2 analogue U46619 and of prostaglandin F2 alpha. In contrast, Iloprost, prostaglandin E2, and sodium nitroprusside promoted stellate-cell relaxation; for example, 82, 83 and 71% of stellate cells relaxed 5, 10, and 20 min, respectively, after addition of 500 microM sodium nitroprusside to contacted cells. Prostaglandin E2 and Iloprost led to elevation of cAMP levels in stellate cells from a basal value of 9.2 +/- 0.8 pmol/well to 55.1 +/- 8.0 and 122.2 +/- 12.2 pmol/well 10 min after addition of prostaglandin E2 (5 microM) and Iloprost (5 microM), respectively, in the presence of 3-isobutyl-1-methylxanthine (0.5 mM). However, sodium nitroprusside was a trigger for cGMP accumulation. Intracellular cGMP increased from a basal value of 0.9 +/- 0.07 pmol/well to 13.4 +/- 6.7 pmol/well 10 min after addition of 500 microM sodium nitroprusside into the medium. It is interesting that Iloprost and sodium nitroprusside also induced the disappearance of actin stress fibers in contracted cells; F-actin stress fibers became less numerous and de-aggregated; more than 90% of stellate cells were void of stress fibers after 10 microM Iloprost treatment for 30 min. Thus, endothelin 1, eicosanoids and sodium nitroprusside are able to modulate the contractility of stellate cells.(ABSTRACT TRUNCATED AT 400 WORDS)

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1993

Insulin-mimetic actions of phorbol ester in cultured adult rat hepatocytes. Lack of phorbol-ester-elicited inhibition of the insulin signal.

The actions of the phorbol ester phorbol 12-myristate 13-acetate (PMA) on glucose metabolism, amino acid transport and enzyme inductions were studied in primary cultures of adult-rat hepatocytes and compared with the effects of insulin. PMA and insulin stimulated glycolysis 5- and 7-fold respectively. The half-maximal effective dose of PMA was 60 nM. Stimulation of glycolysis was accompanied by an insulin- or PMA-dependent and okadaic acid-sensitive activation of 6-phosphofructo-2-kinase and pyruvate kinase, as well as by an increase in fructose 2,6-bisphosphate. Glucose production from glycogen was decreased to 50% by PMA and to 15% by insulin, whereas glycogen synthesis was stimulated 2- and 7-fold respectively. PMA also increased aminoisobutyrate uptake, induced ornithine decarboxylase and counteracted the glucagon-dependent induction of phosphoenolpyruvate carboxykinase. PMA strongly antagonized the hormonal activation of glycogen synthesis, but all other insulin actions assayed were not decreased by the phorbol ester. Whereas additive effects of PMA and insulin were not detected, PMA and a simultaneous increase in the glucose concentration had additive effects on glycolysis and glycogen metabolism. Cell exposure to insulin resulted in receptor autophosphorylation and a more than 10-fold activation of the receptor tyrosine kinase. PMA did not alter these effects, and also had no effect on the receptor phosphorylation status in the absence of insulin. Long-term (15 h) pretreatment of the cells with PMA abolished all PMA effects, but not the insulin effects. It is concluded that PMA does not generally antagonize the action of insulin in differentiated adult hepatocytes, and that insulin and PMA may use related signal-transduction pathways.

Aminoisobutyric Acids↗
PubMed1993

[Long-term follow-up of anti-tachycardia surgery in patients with ventricular tachycardia].

From March 1980 to May 1992 mapping guided surgery was performed in 132 patients with drug-refractory recurrent ventricular tachycardia. There were 121 patients (group I) with coronary disease and 11 patients (group II) had noncoronary ventricular tachycardia. Patients in group I underwent subendocardial resection and cryoablation was performed in group II patients. Perioperative mortality (< 30 days after surgery) was 8% (10/132 patients). During the mean follow-up of 41 +/- 24 months, 37/122 patients (30%) died, 35/111 patients in group I (32%) and 2/11 patients in group II (18%) (p = 0.29). In group I, sudden death occurred in 8/111 patients (7%) and cardiac death in 23/111 patients (21%); in group II, 1/11 patients (9%) died from sudden and 1/11 patients (9%) from cardiac death. Nonfatal recurrences occurred significantly more frequently in group II (6/11 patients, 55%) than in group I (16/111 patients, 14%) (p < 0.01). During the follow-up functional class of heart failure improved in 69 patients (57%), remained constant in 27 patients (22%) and decreased in the remaining 26 patients (21%). The surgical approach to control ventricular tachycardia has low rates of sudden death and nonfatal recurrences in patients with drug-refractory ischemic ventricular tachycardia. Patients with noncoronary disease had a high incidence of nonfatal ventricular tachycardia after surgery and should be considered for other therapeutic approaches in the future.

Adolescent↗
PubMed1993

Characterization of cDNA clones encoding a major microneme antigen of Sarcocystis muris (Apicomplexa) cyst merozoites.

Two monoclonal antibodies directed against a microneme antigen of Sarcocystis muris cyst merozoites (16/17 kDa band doublet) were used to isolate cDNA clones from a lambda ZAP expression library. Restriction analysis revealed that the inserts were highly similar, with sizes ranging between 1.8 and 2.3 kb. In addition, a full-length cDNA insert of 2.6 kb was obtained by hybridization screening. On Northern blots, a single mRNA species of 2.7 kb was detected by a cDNA-derived probe. Southern blot hybridization suggests that the gene is present as a single copy. The nucleotide sequence of the full-length clone contains a single reading frame with a coding capacity of 26.5 kDa. The hypothetical polypeptide consists of a putative N-terminal signal peptide followed by a hydrophilic domain of unknown function, and the mature protein sequence. After purifying the 16/17 kDa antigen from cyst merozoites, a partial N-terminal amino acid sequence was obtained. Thus, the identity of the cDNA sequence was confirmed. The deduced sequence of the mature protein is predominantly hydrophilic and rich in cysteine (8.7%). Database searching suggested weak homologies of the hypothetical polypeptide to plasma kallikrein, tenascin and blood coagulation factors.

Amino Acid Sequence↗
PubMed1993

Hormonal regulation of transforming growth factor beta-2 expression in human prostate cancer.

We have previously shown that a transforming factor-beta species (TGF beta) is a hormonally regulated negative growth factor in estrogen responsive MCF-7 human breast cancer cells. We now demonstrate that androgen withdrawal leads to a significant stimulation of TGF beta-2 mRNA in the androgen-responsive human prostate carcinoma cell line LNCaP. These data indicate that TGF beta-2 is a marker of (anti)androgen action in human prostate cancer in vitro. Based on these results we addressed the question of whether TGF beta-2 represented a marker of (anti)androgen action in prostate cancer in vivo: expression of TGF beta mRNA was determined by RNAase protection analysis in normal and malignant prostate tissue obtained from 9 prostate carcinoma patients without endocrine therapy. In parallel, the nuclear dihydrotestosterone (DHT) concentration was measured as an indicator of androgen stimulation in the same tissues. The following results were obtained. Both normal and cancerous tissues show nuclear accumulation of DHT indicating a functional androgen receptor system. TGF beta-2 is equally expressed in both normal and cancerous tissue. Expression of TGF beta-2 and nuclear DHT concentrations are correlated in both benign and malignant tissue. We conclude that TGF beta-2 is a marker of (anti)hormonal action in androgen-dependent tissue.

Androgens↗
PubMed1993

Treatment of chronic hepatitis B with interferon alpha-2b and interleukin-2.

A total of 37 patients with histologically confirmed chronic viral hepatitis B and presence of HBV-DNA and HBsAg in the serum were treated in a randomized, prospectively controlled multicenter trial either with recombinant IFN alpha-2b alone or a combination of IFN alpha-2b and recombinant IL-2. Twenty-two patients from group A were treated with 3 MU of IFN alpha-2b s.c. thrice weekly for 5 months. Starting at month 2 IL-2 was added: priming doses of 1.5 million CU were given s.c. on the first 2 days of each of the remaining 3 months, followed by maintenance doses of 0.3 million CU daily for 5 days per week. Fifteen patients from group B received 5 MU of IFN alpha-2b s.c. thrice weekly for 5 months. Five patients from group A (24%) and 4 patients from group B (28%) cleared HBV-DNA and HBeAg from the serum, and normalized elevated serum aminotransferase activities. The response rate in both groups did not differ significantly. Since side effects were more pronounced during combination therapy than in IFN alpha-2b monotherapy, it is suggested that treatment with IFN alpha-2b alone is preferable to a regimen of IFN alpha-2b/IL-2 applied according to the above schedule.

Adult↗
PubMed1993

A study of the safety and survival of the adoptive transfer of genetically marked syngeneic lymphocytes in HIV-infected identical twins.

This phase I/II pilot project will evaluate the survival, tolerance, safety, and efficacy of infusions of activated, gene marked, syngeneic T lymphocytes obtained from HIV seronegative identical twins on the functional immune status of HIV infected twin recipients. T cells from each seronegative twin will be obtained by periodic apheresis, separated into CD4 and CD8 enriched populations by monoclonal antibody affinity binding techniques, induced to polyclonal proliferation with anti-CD3 and rIL-2 stimulation, transduced with distinctive neoR retroviral vectors, and expanded 10-1,000 fold in numbers during approximately 2 weeks of culture. These marked T cell fractions will then be infused into the seropositive twins and the survival of the uniquely marked T cell populations will be monitored by vector-specific PCR, while the recipients' functional immune status is monitored by standard in vitro and in vivo testing protocols. A total of 3 cycles of treatment will be given at intervals of 6 weeks between infusions.

Adolescent↗
PubMed1993

Urinary endothelin: a possible biological marker of renal damage.

Endothelin (ET) is a powerful vasoconstrictor peptide synthesized and secreted by the vascular endothelium. Significant amounts of ET are also produced by nonendothelial cells, mainly tubular-epithelial and mesangial cells. Large amounts of ET are found in the urine compared with the small amounts present in blood. Because most of the ET filtered from plasma is subject to degradation by neutral endopeptidase (EC 3.4.24.11) in the proximal tubule, urinary ET is probably of renal origin. The range of urinary ET excretion in healthy persons is 20 to 90 ng/day. The excretion of endothelin is modulated by several mechanical and chemical stimuli such as angiotensin II, phenylephrine, radiocontrast media, cyclosporine, and cis-platin. In addition, enhanced urinary ET excretion has been found in several forms of renal failure, both acute and chronic, and in diabetes mellitus. Thus, urinary ET has the potential of serving as a marker for renal disease.

Amino Acid Sequence↗
PubMed1993

Regulation of the urinary excretion of endothelin in the rat.

The regulation of the urinary excretion of endothelin (UETV) and its clinical significance has not yet been established. The present study was designed to examine the effect of angiotensin II (A-II), arginine vasopressin (AVP), and nifedipine on UETV. Anesthetized Munich-Wistar rats were infused with low (50 ng/kg/min) and high (500 ng/kg/min) doses of A-II for 30 min. Both doses significantly increased UETV, from nondetectable (ND) levels to 155 +/- 54 (P < .03) and 450 +/- 86 fg/min (P < .001), respectively. This effect was accompanied by a significant increase in urine flow (UV), from 6 +/- 1 to 67 +/- 12 and 89 +/- 10 microL/min, and in mean arterial pressure (MAP), from 139 +/- 4 to 187 +/- 5 and 217 +/- 3 mm Hg. Infusions of A-II with its nonspecific antagonist, saralasin, resulted in a further increase in UETV to 647 +/- 126 and 782 +/- 117 fg/min (P < .002), respectively. However, infusion of A-II with its specific antagonist, losartan, completely blocked its stimulatory effect on UETV. Infusion of AVP, 10 or 100 mU/kg/h, produced increases in MAP, from 134 +/- 3 to 165 +/- 7 and 203 +/- 4 mm Hg, and in UV from 6 +/- 1 to 37 +/- 6 and 97 +/- 17 microL/min, comparable to A-II, but AVP did not have a marked effect on UETV.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

Chronic (or healed) myocarditis mimicking arrhythmogenic right ventricular dysplasia.

The aetiology of arrhythmogenic right ventricular dysplasia is still unknown, and there are few reports on familial coincidence in the literature. A case of a previously healthy man with an episode of acute myocarditis is described. After recovery from acute myocarditis, the patient was resuscitated from aborted sudden cardiac death 16 months later. Angiographic and electrophysiological evaluation suggested the pattern of arrhythmogenic right ventricular dysplasia. The case seems to suggest that arrhythmogenic right and/or left ventricular dysplasia could be mimicked by chronic (or healed) myocarditis.

Biopsy↗
PubMed1993

Role of interventional therapy in patients with coronary heart disease and life-threatening ventricular tachyarrhythmias.

This study includes 357 patients with coronary heart disease and life-threatening ventricular tachyarrhythmias. Thirty-three patients (10%) underwent direct current (DC) catheter ablation (group 1), 121 (34%) mapping-guided surgery (group 2) and 203 (56%) received an implantable cardioverter defibrillator (ICD) (group 3). The mean follow-up was 35 +/- 25 months in group 1, 41 +/- 37 months in group 2 and 22 +/- 22 months in group 3. During follow-up, 6 patients (18%) died in group 1, 45 (37%) in group 2 and 46 (23%) in group 3. Sudden death occurred in two patients (6%) in group 1, 10 patients (8%) in group 2 and eight patients (4%) in group 3. Non-fatal recurrences group were observed in 19 patients (57%) in group 1 and in 16 patients (14%) in group 2. ICD discharges occurred in 175/203 patients (86%) in group 3 with a mean number of 18 +/- 28 ICD shocks per patient. Our data show that catheter ablation has a low incidence of sudden death but a high incidence of non-fatal recurrences. Mapping-guided surgery yields low rates of sudden death or recurrence. Patients with an ICD have a low sudden death rate. A treatment algorithm is necessary to evaluate patients at high risk for sudden death and to choose the right patient for the right treatment.

Adolescent↗
PubMed1993

Double parathyroid adenomas. Clinical and biochemical characteristics before and after parathyroidectomy.

OBJECTIVE: There is considerable debate about whether double parathyroid adenomas are a discrete entity or represent hyperplasia with parathyroid glands of varying sizes. This distinction is important because it impacts on the extent of parathyroid resection and the success of the parathyroid operation. SUMMARY BACKGROUND DATA: Double parathyroid adenomas have been reported to occur in 1.7% to 9% of patients with primary hyperparathyroidism (HPT). It is important for surgeons to differentiate between double adenoma and hyperplasia with glands of varying sizes using gross examination during the initial procedure because microscopic findings of a small biopsy specimen at frozen-section examination may not be diagnostic. METHODS: From 1982 to 1992, 416 unselected patients (309 women and 107 men) with primary HPT without familial HPT or multiple endocrine neoplasia (MEN) were treated by one surgeon at the University of California at San Francisco. Double adenoma occurred in 49 patients, solitary adenoma in 309 patients, and hyperplasia in 58 patients. The authors analyzed the clinical manifestations, the preoperative and postoperative serum levels of calcium, phosphate, and parathyroid hormone (PTH), and the success rate and outcome after parathyroidectomy and compared their results in 49 patients with double adenomas to the results for patients with solitary adenomas or hyperplasia. RESULTS: Ten of the patients with double adenomas (20.4%) were referred for persistent HPT after removal of one abnormal parathyroid gland. The ages of the patients with double adenoma, single adenoma, and hyperplasia were 61 +/- 14, 56 +/- 15, and 58 +/- 7 years, respectively. Fatigue, muscle weakness, and bone pain were common in patients with double adenomas, whereas nephrolithiasis occurred more frequently in patients with solitary adenoma (p = 0.0001). Serum calcium and PTH levels (per cent of upper limit of normal) fell from 11.5 +/- 1.2 mg/dL and 487% to 9.5 +/- 0.8 mg/dL and 61% for patients with double adenomas; from 11.9 +/- 0.9 mg/dL and 378% to 9.3 +/- 1.4 mg/dL and 101% for patients with single adenoma; and from 10.9 +/- 0.5 mg/dL and 418% to 9.1 +/- 0.7 mg/dL and 94% for patients with hyperplasia, respectively. There was no recurrence in the patients with double adenomas with a mean follow-up time of 5.8 years. CONCLUSIONS: Double adenomas are a discrete entity and occur more often in older patients. Patients with double adenomas can be successfully treated by removal of the two abnormal glands.

Adenoma↗
PubMed1993

Initial experience with a new transvenous defibrillation system.

The clinical efficacy and safety of a new bidirectional transvenous defibrillation endocardial lead system (ELS) was studied in 39 patients with ventricular tachycardia (VT) or fibrillation (VF). There were 28 patients with coronary disease and 11 patients with nonischemic VT/VF. Fourteen patients received the ELS combined with antitachycardia pacing devices (Ventak PRx 1700, CPI) and 25 patients with the Ventak P or P2 (CPI). Implantation of the ELS was attempted in 47 patients. Intraoperatively, the mean defibrillation threshold (DFT) was > 25 joules in five patients and no reliable ELS position was found in three other patients. These eight patients underwent thoracotomy and epicardial leads implantation. The mean DFT was < or = 20 joules in all 39 patients and the mean DFT was 18 joules. During the mean follow-up of 8 +/- 2 months two patients (5%) died suddenly. Complications occurred in two patients (5%).

Cardiac Catheterization↗
PubMed1993

Clinical efficacy and safety of the new cardioverter defibrillator systems.

Clinical efficacy and safety of two new third-generation implantable cardioverter defibrillators (ICD) were studied in 38 patients with ventricular tachycardia (VT) or fibrillation (VF). There were 31 patients with coronary disease, three patients with right ventricular dysplasia, one patient with dilated cardiomyopathy, and three patients with valvular disease. Twenty-four patients (group I) received an ICD with monophasic (Ventak PRx 1700, CPI) and 14 patients (group II) with biphasic shocks (Cadence V 100, Ventritex). Intraoperatively, the mean defibrillation threshold was significantly lower in group II than in group I, both in patients with induced VT (group I 11.0 +/- 6.3 joules; group II 5.8 +/- 1.3 joules) (P < 0.01) and induced VF (group I 17.5 +/- 4.6 joules; group II 9.6 +/- 5.2 joules) (P < 0.01). During the mean follow-up of 12 +/- 7 months four patients (11%) died. 865 arrhythmia events (AE) occurred and were terminated by ATP (671 VTs, 78%). Acceleration of VTs was observed in 28 AE (3%) and ATP was unable to interrupt 58 AE (7%). ICD shocks were delivered as a first therapy in 108 AE (13%).

Cardiac Catheterization↗
PubMed1993

Ventricular tachycardia surgery in 1992: did the automatic defibrillator change this approach?

The role of ventricular tachycardia (VT) surgery has been changed since the automatic implantable cardioverter defibrillator (ICD) is available. We studied the follow-up of 131 patients who underwent mapping guided surgery due to recurrent VT refractory to antiarrhythmic drug treatment. There were 65 patients operated upon between 1980-1985 (group I) and 66 patients between 1986-1991 (group II). Ten patients (8%) died perioperatively (< 3 weeks after surgery) [7/65 patients, 11%, in group I and 3/66 patients, 5%, in group II (P = 0.15)]. During a mean follow-up of 41 +/- 24 months, 38 of 121 patients died (31%), significantly more patients in group I (24/58 patients, 41%) than in group II (14/63 patients, 22%) (P < 0.05). In group I, there was a higher incidence of sudden (7/58 patients, 12%) or cardiac death (15/58 patients, 26%) than in group II (sudden death 4/63 patients, 6%, cardiac death 7/63 patients, 11%) (P < 0.05). There was a similar incidence of VT recurrences between group I (9/65 patients, 14%) and group II (9/66 patients, 14%). Our data show that the indication for VT surgery has changed since the ICD is available because of better patient selection.

Cardiac Catheterization↗